1. Field of the Invention
The invention relates to an apparatus and a method for folding and sealing a work piece, and more particularly to such an apparatus and method utilizing electrical high frequency sealing means.
2. Background of the Invention
The folding and sealing apparatus and method of the present invention have many applications. While not intended to be so limited, for purposes of an exemplary showing the present invention will be described in its application to the manufacture of parts for the shoe industry, and in a particular example to the folding and sealing of the edges of a shoe vamp and to the attachment of a reinforcing layer or a liner to the vamp.
Heretofore, prior art workers have provided apparatus for folding the edges of parts such as a shoe vamp. An exemplary apparatus is taught, for example, in United States Letters Patent 3,073,141. In the usual use of such apparatus, the edges of the work piece to be folded are generally precoated with a rubberbase adhesive or the like so that they become temporarily bonded after the folding step. Thereafter, the folded edges are additionally stitched together.
Prior art workers have also heretofore used high frequency electricity to bond folded parts together permanently. Under these circumstances, the parts are folded in one operation and subsequently heat sealed together in a separate operation.
Where a part such as a vamp is to be provided with a liner, the liner is cut oversize, stitched to the vamp and thereafter trimmed. If reinforcement is to be applied to the part that is generally accomplished as a separate step prior to the folding step.
The present invention provides a folding and sealing apparatus and method by which the edges of a vamp may be folded and sealed by high frequency electricity during a single cycle of the apparatus. Where reinforcement is to be associated with the work piece, this can be accomplished during the same cycle. A liner, precut to final size, can be heat sealed to the vamp in a second cycle.
Through the use of the apparatus of the present invention and the practice of the methods taught herein, the above mentioned operations are generally simplified. The parts may be heat sealed by an electrode incorporated within the apparatus and connected to a source of high frequency current. The sealing step may be accomplished in a variety of modes with the same apparatus. Finally, the invention lends itself well to the use of unsupported, man-made material compatable with high frequency sealing techniques or materials precoated with an adhesive compatable with such techniques.